Yellowing of Tomato leaves

It sounds as if the tomatoes that you planted outside are stressed. Did you harden them off before planting outside also if it has been cold or windy that will have an effect. Although it is normal not to feed toms until the first truss has set it might help to start feeding now. The other possibility is a magnesium deficiency - you could look on the internet to see what it looks like - although not so likely on outdoor toms. If so drenching the plants with Epson salts can help - at the rate of about a cup to a full watering can.